Question

Which of the given reactions are counted as balanced reactions?

(a) H2 + O2 → 2H2O

(b) 4Al + 3O2 → 2Al2O3

(c) Mg(OH)2 + 2HNO3 → 2Mg(NO3)2 + 2H2O

(d) N2 + 3H2 → NH3

This question was addressed to me in an online quiz.

This intriguing question originated from Stoichiometry and Stoichiometric Calculations in chapter Chemistry Basic Concepts of Chemistry – Class 11

Answer 1

The correct option is (b) 4Al + 3O2 → 2Al2O3

Best explanation: 4Al + 3O2 → 2Al2O3 is a balanced reaction because the number of atoms of different elements on both sides is equal. The correctly balanced equations of the rest are 2H2 + O2 → 2H2O; Mg(OH)2 + 2HNO3 → Mg(NO3)2 + 2H2O and N2 + 3H2 → 2NH3.